Reconstrução de Superfícies usando um Scanner 3D de Luz Estruturada

Ao longo dos últimos anos, os scanners 3D têm tido uma utilização crescente nas mais variadas áreas. Desde a Medicina à Arqueologia, passando pelos vários tipos de indústria, ´e possível identificar aplicações destes sistemas. Essa crescente utilização deve-se, entre vários factores, ao aumento dos recursos computacionais, à simplicidade e `a diversidade das técnicas existentes, e `as vantagens dos scanners 3D comparativamente com outros sistemas. Estas vantagens são evidentes em áreas como a Medicina Forense, onde a fotografia, tradicionalmente utilizada para documentar objectos e provas, reduz a informação adquirida a duas dimensões. Apesar das vantagens associadas aos scanners 3D, um factor negativo é o preço elevado. No âmbito deste trabalho pretendeu-se desenvolver um scanner 3D de luz estruturada económico e eficaz, e um conjunto de algoritmos para o controlo do scanner, para a reconstrução de superfícies de estruturas analisadas, e para a validação dos resultados obtidos. O scanner 3D implementado ´e constituído por uma câmara e por um projector de vídeo ”off-the-shelf”, e por uma plataforma rotativa desenvolvida neste trabalho. A função da plataforma rotativa consiste em automatizar o scanner de modo a diminuir a interação dos utilizadores. Os algoritmos foram desenvolvidos recorrendo a pacotes de software open-source e a ferramentas gratuitas. O scanner 3D foi utilizado para adquirir informação 3D de um crânio, e o algoritmo para reconstrução de superfícies permitiu obter superfícies virtuais do crânio. Através do algoritmo de validação, as superfícies obtidas foram comparadas com uma superfície do mesmo crânio, obtida por tomografia computorizada (TC). O algoritmo de validação forneceu um mapa de distâncias entre regiões correspondentes nas duas superfícies, que permitiu quantificar a qualidade das superfícies obtidas. Com base no trabalho desenvolvido e nos resultados obtidos, é possível afirmar que foi criada uma base funcional para o varrimento de superfícies 3D de estruturas, apta para desenvolvimento futuro, mostrando que é possível obter alternativas aos métodos comerciais usando poucos recursos financeiros.

3D-nanostructured Au electrodes for the event-specific detection of MON810 transgenic maize

In the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis.

Estudo Focado no Utilizador de Software Gratuito para Modelação e Visualização 3D Realista

Computação gráfica um campo que tem vindo a crescer bastante nos últimos anos, desde áreas como cinematográficas, dos videojogos, da animação, o avanço tem sido tão grande que a semelhança com a realidade é cada vez maior. Praticamente hoje em dia todos os filmes têm efeitos gerados através de computação gráfica, até simples anúncios de televisão para não falar do realismo dos videojogos de hoje. Este estudo tem como objectivo mostrar duas alternativas no mundo da computação gráfica, como tal, vão ser usados dois programas, Blender e Unreal Engine. O cenário em questão será todo modelado de raiz e será o mesmo nos dois programas. Serão feitos vários renders ao cenário, em ambos os programas usando diferentes materiais, diferentes tipos de iluminação, em tempo real e não de forma a mostrar as várias alternativas possíveis.

Building 3D City Models: Testing and Comparing Laser Scanning and Low-Cost UAV Data Using FOSS Technologies

Contém resumo

Development of human central nervous system 3D in vitro models for preclinical research

Neurological disorders are a major concern in modern societies, with increasing prevalence mainly related with the higher life expectancy. Most of the current available therapeutic options can only control and ameliorate the patients’ symptoms, often be-coming refractory over time. Therapeutic breakthroughs and advances have been hampered by the lack of accurate central nervous system (CNS) models. The develop-ment of these models allows the study of the disease onset/progression mechanisms and the preclinical evaluation of novel therapeutics. This has traditionally relied on genetically engineered animal models that often diverge considerably from the human phenotype (developmentally, anatomically and physiologically) and 2D in vitro cell models, which fail to recapitulate the characteristics of the target tissue (cell-cell and cell-matrix interactions, cell polarity). The in vitro recapitulation of CNS phenotypic and functional features requires the implementation of advanced culture strategies that enable to mimic the in vivo struc-tural and molecular complexity. Models based on differentiation of human neural stem cells (hNSC) in 3D cultures have great potential as complementary tools in preclinical research, bridging the gap between human clinical studies and animal models. This thesis aimed at the development of novel human 3D in vitro CNS models by integrat-ing agitation-based culture systems and a wide array of characterization tools. Neural differentiation of hNSC as 3D neurospheres was explored in Chapter 2. Here, it was demonstrated that human midbrain-derived neural progenitor cells from fetal origin (hmNPC) can generate complex tissue-like structures containing functional dopaminergic neurons, as well as astrocytes and oligodendrocytes. Chapter 3 focused on the development of cellular characterization assays for cell aggregates based on light-sheet fluorescence imaging systems, which resulted in increased spatial resolu-tion both for fixed samples or live imaging. The applicability of the developed human 3D cell model for preclinical research was explored in Chapter 4, evaluating the poten-tial of a viral vector candidate for gene therapy. The efficacy and safety of helper-dependent CAV-2 (hd-CAV-2) for gene delivery in human neurons was evaluated, demonstrating increased neuronal tropism, efficient transgene expression and minimal toxicity. The potential of human 3D in vitro CNS models to mimic brain functions was further addressed in Chapter 5. Exploring the use of 13C-labeled substrates and Nucle-ar Magnetic Resonance (NMR) spectroscopy tools, neural metabolic signatures were evaluated showing lineage-specific metabolic specialization and establishment of neu-ron-astrocytic shuttles upon differentiation. Chapter 6 focused on transferring the knowledge and strategies described in the previous chapters for the implementation of a scalable and robust process for the 3D differentiation of hNSC derived from human induced pluripotent stem cells (hiPSC). Here, software-controlled perfusion stirred-tank bioreactors were used as technological system to sustain cell aggregation and dif-ferentiation. The work developed in this thesis provides practical and versatile new in vitro ap-proaches to model the human brain. Furthermore, the culture strategies described herein can be further extended to other sources of neural phenotypes, including pa-tient-derived hiPSC. The combination of this 3D culture strategy with the implemented characterization methods represents a powerful complementary tool applicable in the drug discovery, toxicology and disease modeling.

Does abdominoplasty with liposuction of the love handles yield a shorter scar? An analysis with abdominal 3D laser scanning.

The aim of this study was to evaluate the combination of abdominoplasty with liposuction of both flanks with regards to length of scar, complications, and patient's satisfaction. A retrospective analysis of 35 patients who underwent esthetic abdominoplasty at our institution between 2002 and 2004 was performed. Thirteen patients underwent abdominoplasty with liposuction of both flanks, 22 patients underwent conventional abdominoplasty. Liposuction of the flanks did not increase the rate of complications of the abdominoplasty procedures. We found a tendency toward shorter scars in patients who underwent abdominoplasty combined with liposuction of the flanks. Implementation of 3-dimensional laser surface scanning to objectify the postoperative outcomes, documented a comparable degree of flatness of the achieved body contouring in both procedures. 3-dimensional laser surface scanning can be a valuable tool to objectify assessment of postoperative results.

Temporal SNR characteristics in segmented 3D-EPI at 7T.

Three-dimensional segmented echo planar imaging (3D-EPI) is a promising approach for high-resolution functional magnetic resonance imaging, as it provides an increased signal-to-noise ratio (SNR) at similar temporal resolution to traditional multislice 2D-EPI readouts. Recently, the 3D-EPI technique has become more frequently used and it is important to better understand its implications for fMRI. In this study, the temporal SNR characteristics of 3D-EPI with varying numbers of segments are studied. It is shown that, in humans, the temporal variance increases with the number of segments used to form the EPI acquisition and that for segmented acquisitions, the maximum available temporal SNR is reduced compared to single shot acquisitions. This reduction with increased segmentation is not found in phantom data and thus likely due to physiological processes. When operating in the thermal noise dominated regime, fMRI experiments with a motor task revealed that the 3D variant outperforms the 2D-EPI in terms of temporal SNR and sensitivity to detect activated brain regions. Thus, the theoretical SNR advantage of a segmented 3D-EPI sequence for fMRI only exists in a low SNR situation. However, other advantages of 3D-EPI, such as the application of parallel imaging techniques in two dimensions and the low specific absorption rate requirements, may encourage the use of the 3D-EPI sequence for fMRI in situations with higher SNR.

Ultra-high-resolution 3D imaging of atherosclerosis in mice with synchrotron differential phase contrast: a proof of concept study.

The goal of this study was to investigate the performance of 3D synchrotron differential phase contrast (DPC) imaging for the visualization of both macroscopic and microscopic aspects of atherosclerosis in the mouse vasculature ex vivo. The hearts and aortas of 2 atherosclerotic and 2 wild-type control mice were scanned with DPC imaging with an isotropic resolution of 15 μm. The coronary artery vessel walls were segmented in the DPC datasets to assess their thickness, and histological staining was performed at the level of atherosclerotic plaques. The DPC imaging allowed for the visualization of complex structures such as the coronary arteries and their branches, the thin fibrous cap of atherosclerotic plaques as well as the chordae tendineae. The coronary vessel wall thickness ranged from 37.4 ± 5.6 μm in proximal coronary arteries to 13.6 ± 3.3 μm in distal branches. No consistent differences in coronary vessel wall thickness were detected between the wild-type and atherosclerotic hearts in this proof-of-concept study, although the standard deviation in the atherosclerotic mice was higher in most segments, consistent with the observation of occasional focal vessel wall thickening. Overall, DPC imaging of the cardiovascular system of the mice allowed for a simultaneous detailed 3D morphological assessment of both large structures and microscopic details.

Petrography and geochemistry of the McArthur Township area, Ontario /

The McArthur Township area in the Archean Abitibi Belt of northeast Ontario contains northwesterly trending volcanic rocks which are located on a limb of a large syncline. The axial trace of the syncline passes through the adjacent Douglas Township. The Archean volcanic rocks and associated sedimentary rocks are intruded and deformed by two large plutons and a few smaller hypabyssal intrusions. A petrographic and geochemical study of the Precambrian rocks exposed 1n the study area was undertaken in order to investigate the metamorphic grade and geochemical characteristics of the rocks. All the samples were studied with the microscope and analysis of 20 major and trace elements were determined on a selection of the less altered specimens by x-ray fluorescence. Three different periods of igneous activity have occurred in the study area. The first two periods were dominated by volcanic extrusive rocks accompanied by gabbroic sills. The third cycle is the diapiric intrusion of the granitic plutons and subsequent metamorphism of the older rocks to the low to medium grade. Two periods of sedimentation are also recognized in the study area which occurred after the first and second cycle of volcanism. Chemically, the lavas are subdivided into three main associations: (1) The komatiitic association is characterized by high MgO, high Ni, low Ti02 and a low FeO*/(FeO* + MgO) ratio. They occupy the base of each volcanic cycle and some of the flows exhibit spinifex textures. (2) The tholeiitic association displays distinct iron and titanium enrichment trends in the intermediate membersor -i r (3) The calc-alkaline association contains low FeO* and TI02 and high Ni contents relative to modern calc-alkaline types. They are formed at the end of each cycle of volcanism and overlie the tholeiitic flows. All three associations of the first volcanic cycle are exposed in the study area, while the second cycle is represented by a komatiltic sequence. The volcanic rocks were possibly formed by multiple partial melting of the Archean mantle to produce parental magmas under various P - T conditions.

3D movement and muscle activity patterns in a violin bowing task

Objective: Overuse injuries in violinists are a problem that has been primarily analyzed through the use of questionnaires. Simultaneous 3D motion analysis and EMG to measure muscle activity has been suggested as a quantitative technique to explore this problem by identifying movement patterns and muscular demands which may predispose violinists to overuse injuries. This multi-disciplinary analysis technique has, so far, had limited use in the music world. The purpose of this study was to use it to characterize the demands of a violin bowing task. Subjects: Twelve injury-free violinists volunteered for the study. The subjects were assigned to a novice or expert group based on playing experience, as determined by questionnaire. Design and Settings: Muscle activity and movement patterns were assessed while violinists played five bowing cycles (one bowing cycle = one down-bow + one up-bow) on each string (G, D, A, E), at a pulse of 4 beats per bow and 100 beats per minute. Measurements: An upper extremity model created using coordinate data from markers placed on the right acromion process, lateral epicondyle of the humerus and ulnar styloid was used to determine minimum and maximum joint angles, ranges of motion (ROM) and angular velocities at the shoulder and elbow of the bowing arm. Muscle activity in right anterior deltoid, biceps brachii and triceps brachii was assessed during maximal voluntary contractions (MVC) and during the playing task. Data were analysed for significant differences across the strings and between experience groups. Results: Elbow flexion/extension ROM was similar across strings for both groups. Shoulder flexion/extension ROM increaslarger for the experts. Angular velocity changes mirrored changes in ROM. Deltoid was the most active of the muscles assessed (20% MVC) and displayed a pattern of constant activation to maintain shoulder abduction. Biceps and triceps were less active (4 - 12% MVC) and showed a more periodic 'on and off pattern. Novices' muscle activity was higher in all cases. Experts' muscle activity showed a consistent pattern across strings, whereas the novices were more irregular. The agonist-antagonist roles of biceps and triceps during the bowing motion were clearly defined in the expert group, but not as apparent in the novice group. Conclusions: Bowing movement appears to be controlled by the shoulder rather than the elbow as shoulder ROM changed across strings while elbow ROM remained the same. Shoulder injuries are probably due to repetition as the muscle activity required for the movement is small. Experts require a smaller amount of muscle activity to perform the movement, possibly due to more efficient muscle activation patterns as a result of practice. This quantitative multidisciplinary approach to analysing violinists' movements can contribute to fuller understanding of both playing demands and injury mechanisms .

Petrography, geochemistry and structure of the Timmins area, Ontario

Regional structural analysis of the Timmins area indicates four major periods of tectonic deformation. The DI deformation is characterized by a series of isoclinal FI folds which are outlined in the study area by bedding, pillow tops and variolitic flows. The D2 deformation developed the Porcupine Syncline and refolded the Fl folds about a NE. axis. A pervasive S2 foliation developed during low grade (greenschist) regional metamorphism associated with the D2 deformation. The S2 foliation developed south of the Destor-Porcupine Break. The third phase of tectonic D3 deformation is recognized by the development of a S3 sub-horizontal crenulation cleavage which developed on the plane of the S2 foliation. No meso scopic folds are associated with this deformation. The 8 3 crenulation cleavage is observed south of the Destor-Porcupine Break. The D4 tectonic deformation is recorded as a subvertical S4 crenulation cleavage which developed on the plane of the S2 foliation and also offsets the S3 crenulation cleavage. Macroscopic F4 folds have refolded the F2 axial plane. No metamorphic recrystallization is associated with this deformation. The S4 crenulation cleavage is observed south of the Destor-Porcupine Break. Petrographic evidence indicates that the Timmins area has been subjected to pervasive regional low grade (greenschist) metamorphism which has recrystallized the original mineralogy. South of the study are~ the Donut Lake ultramafic lavas have been subjected to contact medium grade (amphibolite facies) metamorphism associated with the intrusion of the Peterlong Lake Complex. The Archean volcanic rocks of the Timmins area have been subdivided into komatiitic, tholeiitic and calcalkaline suites based on Zr, Ti0 2 and Ni. The three elements were used because of their r e lative immobility during subsequent metamorphic events. Geochemical observations in the Timmins area indicates that the composition of the Goose Lake and Donut Lake Formations are a series of peridotitic, pyroxenitic and basaltic komatiites. The Lower Schumacher Formation is a sequence of basaltic komatiites while the upper part of the Lower Schumacher Formation is an intercalated sequence of basaltic komatiites and low Ti0 2 tholeiites. The variolitic flows are felsic tholeiites in composition and geochemical evidenc e sugg ests that they developed as a n immiscible splitting of a tholeiitic magma. The Upper Schumacher Formation is a sequence of tholeiitic rocks dis p laying a mild iron enrichment. The Krist and Boomerang Formations are the felsic calc-alkaline rocks of the study area which are characteristically pyroclastic. The Redstone Fo rmation is dominantly a calc-alkali ne sequence of volcani c rocks whose minor mafic end me mbers exposed in 1t.he study hav e basaltic komatiitic compositions. Geochemical evidence sugges ts that the Keewatin-type se dimentary rocks have a composition similar to a quartz diorite or a granodiorite. Fi e l d obs ervations and petrographic evidence suggests that they were derived fr om a distal source and now repr esent i n part a turbidite sequence. The Timiskaming-type sedimentary rocks approach the c omp osi t ion of the felsic calc-alkaline rocks of the study area . The basal conglomerate in the study are a sugge s ts that th e uni t was derived fr om a proximal source. Petrographic and ge ochemical evidence suggests that the peridotitic and pyroxenitic komatiites originated as a 35-55% partial melt within the mantle, in excess of 100 Km. depth. The melt ros e as a diapir with the subsequent effusion of the ultramafic lavas, The basaltic komatiites and tholeiitic rocks originated in the mantle from lesser degrees of partial melting and fractionated in low pressure chambers. Geochemical evidence suggests a "genetic link" between the basaltic komatiites and tholeiites, The calc-alkaline rocks developed as a result of the increa.se In PO in the magma chamber. The felsic calcalkaline rocks are a late stage effusion possibly the last major volcanic eruptions in the area.

Petrography, Petrochemistry and petrogenesis of Huronian volcanic rocks of the Elliot Lake region, Ontario

In the Elliot lake region of northern Ontario, Yolcanlc lava piles represent the lowermost units of the Huronian SUpergroup. These rocks general1y trend east-west and belong to the Elliot lake Group. They are s1tuated on the north and south limbs or the QuIrke lake Syncline. The volcanIc rocks of this study contain a secondary minerai assemblage consisting of actinolite, biotite, chlorIte, eptdote/cllnozoislte tttanomagnettte and calcite characteristic of greenschist metamorphism. Compilation of data suggests that metamorphism of the volcanic rocks proceeded between 325- and 425-C and between 2.4 and 4.7 kb. Geochemtcally these lavas represent tholeiitic and calc-alkaline assemblages. The tholeiites are character1sttcally enriched tn Fe and Tt and consist mainly of basalts, basaltic andesites and andesites. These rocks are believed to have formed by the partIal melting of a peridottte source at low P-T. In contrast, the calc-alkaline rocks are depleted in Fe and TI, but show a signIficant enrichment In 51 and Zr; andesIte Is the major rock type for thIs assemblage. I·t Is postUlated that the calc-alkalIne sU1te of rocks was the result of eIther the partIal meltIng of abasaltic·magma at shallow depth, or the melttng of s1al1c crustal materIal due to the added we1ght of tholeiitIc material on an unstable crust and to downwarplng processes Inttlated by convection cells.